The case for independence

Scotland's first minister, Alex Salmond, sees the vote as a once-in-a-lifetime chance to "build a more prosperous and fairer Scotland" by breaking political links to Britain and creating a new Scottish constitution.

North Sea oil revenue is a key issue. A Yes vote could see Scotland potentially gain control of up to 90 per cent of North Sea oil which is in Scottish territorial waters.

Mr Salmond's SNP would also like to see the removal of nuclear missiles from Scottish soil. Trident nuclear missiles are currently on Royal Navy submarines based at the Clyde naval base at Faslane, west of Glasgow.

The SNP is also proposing a defence force that would not be involved in contentious conflicts like the Iraq war. However, it wants an independent Scotland to join NATO, the United Nations and the European Union.

The key issues

Economy and currency

Monarchy

Health care

Energy

Pensions

Immigration

EU membership

Defence

The SNP labels the UK as "one of the most unequal societies in the world".

Mr Salmond says controversial welfare reforms brought in by the coalition government in London should be reversed, and the minimum wage should be raised. The SNP also wants to boost the aged pension from 2016.

He also sees independence as a chance to protect the National Health Service (NHS), accusing the "Westminster elite" of trying to privatise the NHS, cutting services and funding.

Mr Salmond hopes independence will curtail the exodus of Scots from the nation - 70,000 are leaving each year, more than half of them aged 16 to 34.

The SNP leader has recently been invoking "the spirit of Robert the Bruce" - the Scottish king who inflicted a bloody defeat on Edward II's English army at the Battle of Bannockburn, near Stirling, in 1314.

The case for the union

Alistair Darling, a former Labour chancellor of the exchequer, is the leader of the Better Together campaign - a coalition of Labour, Conservative and Liberal Democrat figures who want Scots to vote No to independence.

Mr Darling says Scotland's parliament already has real decision-making powers as part of a strong and secure United Kingdom.

He says in 2008 the UK played a key role in stopping Scotland's banks from collapsing and minimising the impact on Scottish taxpayers, unlike what happened in Ireland and Iceland.

Mr Darling also believes it is unwise for Scotland to turn its biggest market - England - into its biggest economic competitor.

He says separation will create new areas of uncertainty, instability and division and the choice will be irrevocable.

She says the consensus among financial experts is that an independent Scotland would be worse off, with less money to spend on areas like schools and hospitals.

Ms Lamont says if the Yes vote succeeds, Scotland could face a deficit of about 5 per cent of GDP in 2016-17, larger than that of the UK as a whole, requiring tax rises or spending cuts in response.

Scottish Liberal Democrat leader Willie Rennie says: "Harking back to a very different world fails to address the needs of a modern forward-looking nation. Partnership, not past divisions, is something that people in Scotland want."

Former British prime minister Gordon Brown, who is a Scot, says pensions, free health care and access to the BBC are some of the benefits Scotland derives from being part of the UK.

He says through a "pensions partnership" Scotland receives and extra 425 million pounds ($757 million) a year - more than its population would normally be allocated.

Mr Brown says 600,000 Scottish jobs also depend on British companies or exports.

He says Scots also benefit from lower interest rates and "social and cultural connection", because half of Scots have close relatives in the rest of the UK.

Are there implications for Australia?

His remarks were the strongest yet by a foreign leader on the independence debate, and drew the ire of Mr Salmond's office, which said Mr Abbott had "put his foot in it".

Associate Professor Iain Stewart from Macquarie University says if the Yes vote prevails in Scotland, it could seriously affect Australia.

"It could remove our head of state, the monarch, and thus, at least legally, make government in Australia impossible," he said.

"We need to think ahead. We may need to move to a republic and soon."

Professor Stewart says if Scotland regains its independence, a revival of the Scottish monarchy appears a likely option, with Queen Elizabeth installed as Scotland's head of state.

This could fix an issue in Scotland, but create a serious one in Australia.

"It appears that the former throne of Scotland would be revived and [Queen] Elizabeth would be invited to accept it," he said.

"There would then be a 'personal union' - a single person on both thrones - of the monarchies of Scotland and of remaining Britain, as there was for Scotland and England before the two countries united under a single throne in 1707.

"The problem for Australia is that, whatever Elizabeth or her successor may do, they would not occupy a throne of the 'United Kingdom', which is how Australian constitutional law defines our head of state.

"There would no longer be any sovereignty of the United Kingdom on which Australia could draw for its own head of state."